A flexible container holds #"6.70 mol"# of a gas. An additional #"3.50 mol"# of the gas is added to the container until it reaches a final volume of #"25.4 L"# while temperature and pressure are kept constant, what was the initial volume?

1 Answer
Meave60
Nov 5, 2016

The initial volume was 16.7 L.

Explanation:

This problem requires Avogadro's law, which states that the amount (moles) of a gas is directly proportional to its volume, such that if the amount increases, the volume increases and vice versa. You correctly determined the formula to use: #V_1/n_1=V_2/n_2#

Known
#n_1="6.70 mol"#
#V_2="25.4 L"#
#n_2="6.70 mol+3.50 mol"="10.2 mol"#

Unknown
#V_1#

Solution
Rearrange the equation to isolate #V_1#. Substitute the known values into the equation and solve.

#V_1=(V_2n_1)/n_2#

#V_1=(25.4"L"xx6.70cancel"mol")/(10.2cancel"mol")="16.7 L"# rounded to three significant figures

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